feat(napi): add tracing via OXC_LOG:DEBUG (#202)

README.md

@@ -167,6 +167,12 @@ e.g.
 
 The input values are `options`, `path` and `specifier`, the returned value is `ret`.
 
+### NAPI
+
+```
+OXC_LOG=DEBUG your_program
+```
+
 ### Rolldown
 
 ```bash

examples/resolver.rs

@@ -17,6 +17,8 @@ fn main() {
     let options = ResolveOptions {
         alias_fields: vec![vec!["browser".into()]],
         alias: vec![("asdf".into(), vec![AliasValue::from("./test.js")])],
+        extensions: vec![".js".into(), ".ts".into()],
+        extension_alias: vec![(".js".into(), vec![".ts".into()])],
         ..ResolveOptions::default()
     };
 

napi/Cargo.toml

@@ -11,10 +11,11 @@ test       = false
 doctest    = false
 
 [dependencies]
-oxc_resolver = { path = ".." }
-napi         = { version = "2.16.7", default-features = false, features = ["napi3", "serde-json", "async"] }
-napi-derive  = { version = "2.16.6" }
-tokio        = "1.38.0"
+oxc_resolver       = { path = ".." }
+napi               = { version = "2.16.7", default-features = false, features = ["napi3", "serde-json", "async"] }
+napi-derive        = { version = "2.16.6" }
+tokio              = "1.38.0"
+tracing-subscriber = { version = "0.3.18", features = [] }                                                         # Omit the `regex` feature
 
 [build-dependencies]
 napi-build = "2.1.3"

napi/src/lib.rs

@@ -10,9 +10,13 @@ use std::{
 use napi_derive::napi;
 use oxc_resolver::{ResolveOptions, Resolver};
 
-use self::options::{NapiResolveOptions, StrOrStrList};
+use self::{
+    options::{NapiResolveOptions, StrOrStrList},
+    tracing::init_tracing,
+};
 
 mod options;
+mod tracing;
 
 #[napi(object)]
 pub struct ResolveResult {
@@ -47,6 +51,7 @@ pub struct ResolverFactory {
 impl ResolverFactory {
     #[napi(constructor)]
     pub fn new(options: NapiResolveOptions) -> Self {
+        init_tracing();
         Self { resolver: Arc::new(Resolver::new(Self::normalize_options(options))) }
     }
 

napi/src/tracing.rs

@@ -0,0 +1,23 @@
+use std::sync::OnceLock;
+
+use tracing_subscriber::{filter::Targets, prelude::*};
+
+/// To debug `oxc_resolver`:
+/// `OXC_LOG=DEBUG your program`
+pub fn init_tracing() {
+    static TRACING: OnceLock<()> = OnceLock::new();
+    TRACING.get_or_init(|| {
+        // Usage without the `regex` feature.
+        // <https://github.com/tokio-rs/tracing/issues/1436#issuecomment-918528013>
+        tracing_subscriber::registry()
+            .with(std::env::var("OXC_LOG").map_or_else(
+                |_| Targets::new(),
+                |env_var| {
+                    use std::str::FromStr;
+                    Targets::from_str(&env_var).unwrap()
+                },
+            ))
+            .with(tracing_subscriber::fmt::layer())
+            .init();
+    });
+}